CN114557046A

CN114557046A - Apparatus and method for accessing network in wireless communication system

Info

Publication number: CN114557046A
Application number: CN202080071831.1A
Authority: CN
Inventors: 张宰赫; 金成勋; A.阿吉瓦尔
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2019-08-14
Filing date: 2020-08-14
Publication date: 2022-05-27
Also published as: KR20210020397A; EP4017121A4; EP4017121A1; US20220279595A1; WO2021029751A1

Abstract

The present disclosure relates to a communication technology combining a fifth generation (5G) communication system for supporting a higher data transmission rate than a 4G system with an internet of things (IoT) technology, and a system thereof. The present disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or networked cars, healthcare, digital education, retail commerce, security and security related services, etc.) based on 5G communication technology and internet of things related technology. According to various embodiments of the present disclosure, in a wireless communication system, a terminal may include at least one transceiver and at least one processor coupled with the at least one transceiver, the at least one processor may be configured to receive system information from a cell of a base station, determine whether the cell supports a New Radio (NR) lite based on the system information, and perform a random access procedure for the cell if the cell supports the NR lite, and for the terminal performing the NR lite, at least one of a subcarrier spacing (SCS), a Transport Block (TB) size, or a bandwidth part (BWP) is reduced to a specified value compared to other terminals not performing the NR lite.

Description

Apparatus and method for accessing network in wireless communication system

Technical Field

The present disclosure relates generally to wireless communication systems, and more particularly, to an apparatus and method for accessing a network in a wireless communication system.

Background

In order to meet the increasing demand for wireless data services after the commercialization of fourth-generation (4G) communication systems, an advanced fifth-generation (5G) communication system or first 5G communication system is being developed in an effort. For this reason, the 5G communication system or the former 5G communication system is referred to as a super 4G network communication system or a post Long Term Evolution (LTE) system. To achieve high data rates, 5G communication systems are considered to be implemented in the very high frequency (millimeter wave) band (e.g., 60GHz band). To mitigate path loss of propagation and extend propagation distance in the extremely high frequency band, 5G communication systems are discussing beamforming, massive Multiple Input Multiple Output (MIMO), full-dimensional (FD) -MIMO, array antennas, analog beamforming, and massive antenna techniques. Further, for network enhancements of the system, the 5G communication system is developing technologies such as evolved small cells, advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and reception interference cancellation. In addition, 5G systems are developing hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and Sliding Window Superposition Coding (SWSC) as Advanced Coding Modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and Sparse Code Multiple Access (SCMA) as advanced access technologies.

Meanwhile, the internet is evolving from a human-centric connected network where humans generate and consume information to an internet of things (IoT) network where information is exchanged and processed between distributed elements such as things. Internet of everything (IoE) technology is emerging, where big data processing technology is combined with IoT technology through a connection with a cloud server. To implement IoT, technical elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and technologies such as sensor networks, machine-to-machine (M2M), and Machine Type Communication (MTC) for connections between things are being recently researched. The IoT environment can provide intelligent Internet Technology (IT) services that create new value for human life by collecting and analyzing data generated from connected things. Through convergence and combination between existing IT and various industries, IoT may be applied to fields such as smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart home appliances, and advanced medical services.

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, 5G communication technologies such as sensor network, M2M, and MTC are implemented by schemes such as beamforming, MIMO, and array antennas. The aforementioned application cloud radio access network (cloud RAN) as a big data processing technology may be an example of a convergence of 5G technology and IoT technology.

For a terminal to be implemented at low cost, in the NR communication system, a solution to reduce the complexity of channel access and communication is being discussed.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

Based on the foregoing discussion, the present disclosure provides an apparatus and method for supporting an existing New Radio (NR) terminal to operate in a wide bandwidth while supporting an NR-lite terminal to operate in a narrow bandwidth within a single base station in a wireless communication system.

According to various embodiments of the present disclosure, an operating method of a terminal in a wireless communication system may include receiving system information from a cell of a base station, determining whether the cell supports NR lite based on the system information, and performing a random access procedure for the cell if the cell supports NR lite, and for a terminal performing NR lite, at least one of a subcarrier spacing (SCS), a Transport Block (TB) size, or a bandwidth part (BWP) is reduced to a specified value compared to other terminals not performing NR lite.

According to various embodiments of the present disclosure, a terminal in a wireless communication system may include at least one transceiver and at least one processor coupled with the at least one transceiver, the at least one processor may be configured to receive system information from a cell of a base station, determine whether the cell supports NR lite based on the system information, and perform a random access procedure for the cell if the cell supports NR lite, and for a terminal that performs NR lite, at least one of a subcarrier spacing (SCS), a Transport Block (TB) size, or a bandwidth part (BWP) is reduced to a specified value compared to other terminals that do not perform NR lite.

[ advantageous effects of the invention ]

Apparatuses and methods according to various embodiments of the present disclosure may allow a communication operator to improve communication efficiency by supporting an existing New Radio (NR) terminal supporting a broadband and an NR-lite terminal supporting only a narrowband in a base station.

Effects obtainable from the present disclosure are not limited to the above-described effects, and other effects not mentioned may be clearly understood by those skilled in the art of the present disclosure through the following description.

Drawings

Fig. 1A illustrates an example of a wireless communication system in accordance with various embodiments of the present disclosure.

Fig. 1B illustrates an example of a radio protocol structure in a wireless communication system according to various embodiments of the present disclosure.

Fig. 2A illustrates another example of a wireless communication system in accordance with various embodiments of the present disclosure.

Fig. 2B illustrates another example of a radio protocol structure of a wireless communication system according to various embodiments of the present disclosure.

Fig. 3 illustrates an example of downlink and uplink channel frame structures in beam-based communication in a wireless communication system, according to various embodiments of the present disclosure.

Fig. 4 illustrates an example of a random access procedure in a wireless communication system, in accordance with various embodiments of the present disclosure.

Fig. 5 illustrates an example of a bandwidth part (BWP) operation in a wireless communication system according to various embodiments of the present disclosure.

Fig. 6 illustrates an example of an initial access procedure of a New Radio (NR) -lite terminal in a wireless communication system according to various embodiments of the present disclosure.

Fig. 7 illustrates an example of a random access procedure of an NR-lite terminal in a wireless communication system according to various embodiments of the present disclosure.

Fig. 8 illustrates an example of a capability information transmission procedure of an NR-lite terminal in a wireless communication system according to various embodiments of the present disclosure.

Fig. 9 illustrates an operational flow of an NR-lite terminal for accessing a network in a wireless communication system according to various embodiments of the present disclosure.

Fig. 10 shows a functional configuration of a base station in a wireless communication system according to various embodiments of the present disclosure.

Fig. 11 shows a functional configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure.

Detailed Description

Hereinafter, the operational principle of the present invention will be described in detail with reference to the accompanying drawings. If it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention in describing the present invention, a detailed description thereof will be omitted. Terms to be described are terms defined by considering functions of the present disclosure, which may vary according to intention or practice of a user or operator. Therefore, their definitions should be based on the contents of the entire specification.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meanings as those commonly understood by one of ordinary skill in the art described in the present disclosure. Among the terms used in the present disclosure, terms defined in a general dictionary may be construed to have the same or similar meaning as in the context of the related art, and cannot be construed as ideal or excessively formal meaning unless explicitly defined in the present disclosure. In some cases, even terms defined in the present disclosure cannot be construed as excluding embodiments of the present disclosure.

The hardware-based approach will be described as an example in various embodiments of the present disclosure to be described below. However, various embodiments of the present disclosure include techniques using both hardware and software, and thus do not preclude software-based approaches.

Terms for identifying an access node, terms indicating a network entity, terms indicating a message, terms indicating an interface between network entities, and terms indicating various identification information, which are used in the following explanation, are illustrated only for the convenience of description. Therefore, the present invention is not limited to the terms to be described, and other terms indicating objects having the same technical meaning may be used.

Hereinafter, for convenience of description, the present invention uses terms and names defined in Long Term Evolution (LTE) and New Radio (NR) standards, which are the latest standards defined by the third generation partnership project (3GPP) organization in currently existing communication standards. However, the present invention is not limited by terms and names, and can be equally applied to systems conforming to other standards. In particular, the present invention can be applied to 3GPP NR (fifth generation mobile communication standard).

Also, in the present disclosure, in order to determine whether a specific condition is satisfied or satisfied, expressions such as greater than or less than are used, but this is merely an expression as an example, and does not exclude an expression equal to or greater than or equal to or less than. A condition expressed as "greater than or equal to" may be replaced with "greater than", a condition expressed as "less than or equal to" may be replaced with "less than", and a condition expressed as "greater than or equal to and less than" may be replaced with "greater than and less than or equal to".

Hereinafter, the present disclosure relates to an apparatus and method for accessing a network in a wireless communication system. In particular, the present disclosure relates to a method in 3GPP 5G NR for accessing a network at a terminal simplified with minimum performance according to specific ones of the requirements of existing NR terminals, such as smart watches, and more particularly, an "NR-light/NR-lite" terminal with reduced price and complexity.

Referring to fig. 1A, the wireless communication system includes several evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN) nodebs (enbs) 105, 110, 115, and 120, a Mobility Management Entity (MME)120, and a serving gateway (S-GW) 130. A user equipment (hereinafter, referred to as UE or terminal) 135 accesses an external network through

enbs

105, 110, 115 and 120 and an S-GW 130.

The

enbs

105, 110, 115 and 120 are access nodes of a cellular network and provide radio access to UEs accessing the network. That is, the

enbs

105, 110, 115 and 120 collect and schedule state information such as buffer status, available transmission power status and channel status of the UE to serve traffic of a user, thereby supporting connection between the UE and a Core Network (CN). MME 125 is a device for various control functions and for mobility management functions of the UE and is connected to a plurality of enbs, and S-GW 130 is a device providing data bearers. In addition, MME 125 and S-GW 130 may also perform authentication and bearer management for UEs accessing the network and process packets received from

enbs

105, 110, 115, and 120 or packets to be delivered to

gnbs

105, 110, 115, and 120.

Referring to fig. 1B, the radio protocols of the LTE system include Packet Data Convergence Protocols (PDCP)155 and 190, Radio Link Controls (RLC)160 and 185, and Medium Access Controls (MAC)155 and 190 at the UE and eNB, respectively. The

PDCP

155 and 190 manages operations such as Internet Protocol (IP) header compression/restoration, and the RLC 160 and 195 reconstructs PDCP Packet Data Units (PDUs) to an appropriate size. The

MACs

165 and 190 are connected to several RLC layer devices configured in one UE, and multiplex and demultiplex RLC PDUs to and from MAC PDUs. The

physical layers

170 and 185 channel-encode and modulate upper layer data, generate them into OFDM symbols and transmit them through a radio channel, or demodulate OFDM symbols received through a radio channel and forward them to an upper layer. In addition, the physical layer performs additional error correction using hybrid automatic repeat request (HARQ), and whether or not a packet transmitted by the receiving stage with 1-bit transmission is received. This is referred to as HARQ Acknowledgement (ACK)/Negative Acknowledgement (NACK) information. In LTE, downlink HARQ ACK/NACK information for uplink data transmission is transmitted on a physical hybrid ARQ indicator channel (PHICH) physical channel, although not shown in the figure, a Radio Resource Control (RRC) layer exists above each PDCP layer of the UE and eNB, and the RRC layers may exchange access and measurement related configuration control messages for radio resource control.

Meanwhile, the PHY layer may include one or more frequencies/carriers, and a technique for simultaneously setting and using a plurality of frequencies is referred to as a carrier aggregation technique (hereinafter, referred to as CA). The CA technology can significantly increase the transmission amount by the number of secondary carriers by additionally using a primary carrier and one or more secondary carriers, rather than using only one carrier for communication between a UE and an eNB. Meanwhile, in LTE, a cell in eNB using a primary carrier is referred to as a primary cell or PCell, and a cell in eNB using a subcarrier is referred to as a secondary cell or SCell.

Fig. 2A illustrates another example of a wireless communication system in accordance with various embodiments of the present disclosure. The structure of the wireless communication system shown in fig. 2A may include a system employing NR. According to embodiments, NR may refer to a communication system for achieving high data rate, high reliability, and/or low latency data communication, as compared to LTE. Hereinafter, in the present disclosure, a system to which NR is applied may be simply referred to as an "NR system", "5G communication system", or "next generation mobile communication system". The cells of the NR system may be referred to as "NR cells".

Referring to fig. 2B, a radio access network of a next generation mobile communication system (hereinafter, referred to as NR or 5g) may include a new radio node B (hereinafter, referred to as NR gbb or NR base station) 210 and a new radio core network (NR CN) 205. A new radio user equipment (NR UE or UE)215 may access the external network via the NR gNB 210 and the NR CN 205.

In fig. 2A, the NR gNB 210 may correspond to an eNB of an existing LTE system. The NR gNB is connected with the NR UE 215 through a radio channel and can provide a much better service than the existing node B. In NR, each user service can be served through a shared channel. Therefore, an apparatus for collecting and scheduling state information such as buffer status, available transmission power status, and channel status of the UE is necessary and may be served by the NR gNB 210. One NR gbb may control a plurality of cells. Compared to current LTE, NR can implement ultra-high speed data transmission with a bandwidth greater than the current maximum bandwidth. Furthermore, the beamforming technique may be additionally combined with an Orthogonal Frequency Division Multiplexing (OFDM) technique, which is a radio access technique. Also, an adaptive modulation and coding (hereinafter, referred to as AMC) scheme for determining a modulation scheme and a channel coding rate according to a channel state of the UE may be applied.

The NR CN 205 may perform functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN is a device for managing various control functions of the UE as well as a mobility management function, and may be connected to a plurality of gnbs. Further, according to embodiments, the NR may interwork with existing LTE systems and the NR CN may be connected to the MME 225 through a network interface. The MME may connect to the eNB 230 as an existing gNB.

Fig. 2B illustrates another example of a radio protocol structure of a wireless communication system according to various embodiments of the present disclosure. The radio protocol structure shown in fig. 2B may be a radio protocol structure of an NR system.

Referring to fig. 2B, the radio protocols of the NR system include NR Service Data Adaptation Protocols (SDAP)251 and 295,

NR PDCP

255 and 290,

NR RLC

260 and 285,

NR MAC

265 and 280, and

NR PHYs

270 and 285 in the UE and NR gNB, respectively.

The primary functions of

NR SDAP

251 and 295 may include some of the following functions.

-delivery of user plane data

Mapping between QoS flows and DRBs for DL and UL

-marking QoS flow IDs in DL and UL packets

Reflective QoS flow to DRB mapping for UL SDAP PDUs.

For the SDAP layer device, the UE can be configured with RRC messages whether to use the SDAP layer device's header or the SDAP layer device's functionality for each PDCP layer device, bearer, or logical channel. If the SDAP header is configured, the UE may utilize a non-access stratum (NAS) reflective QoS 1 bit indicator and an Access Stratum (AS) reflective QoS 1 bit indicator of the SDAP header to instruct the UE to update or reconfigure the uplink and downlink QoS flow and data bearer mapping information. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used as data processing priority, scheduling information, etc. for supporting smooth service.

The main functions of the

NR PDCP

255 and 290 may include some of the following functions.

Header compression and decompression ROHC only

-delivery of user data

In-order delivery of upper layer PDUs

Out-of-order delivery of upper layer PDUs

-reordering for received PDCP PDUs

Duplicate detection of lower layer SDU

-retransmission of PDCP SDU

-encryption and decryption

Timer based SDU discard in uplink.

In the above description, the reordering of the NR PDCP device may indicate a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP Sequence Number (SN). The reordering of the NR PDCP device may include a function of delivering data to an upper layer in a rearranged order, may include a function of directly delivering data regardless of an order, may include a function of recording missing PDCP PDUs by rearranging an order, may include a function of reporting a status of the missing PDCP PDUs to a transmitting stage, and may include a function of requesting retransmission of the missing PDCP PDUs.

The main functions of

NR RLC

260 and 285 may include some of the following functions.

-delivery of upper layer PDU

In-order delivery of upper layer PDUs

Out-of-order delivery of upper layer PDUs

Error correction by ARQ

Splicing, segmentation and reassembly of RLC SDUs

-re-segmentation of RLC data PDUs

Reordering of RLC data PDUs

-duplicate detection

-protocol error detection

RLC SDU discard

RLC re-establishment

In the above description, in-order delivery of the NR RLC device may indicate a function of delivering RLC SDUs received from a lower layer to an upper layer in order. In-order delivery of the NR RLC devices may include the functions of re-assembling and delivering an original RLC SDU if it is segmented into several RLC SDUs and received.

In-order delivery of the NR RLC device may include a function of reordering received RLC PDUs based on RLC SNs or PDCP SNs, may include a function of recording missing RLC PDUs by reordering order, may include a function of reporting a status of the missing RLC PDUs to a transmitting stage, and may include a function of requesting retransmission of the missing RLC PDUs.

In-order delivery of the

NR RLC

260 and 285 devices may include a function of sequentially delivering only RLC SDUs preceding the missing RLC SDU to an upper layer if there is the missing RLC SDU. Further, the in-order delivery function of the NR RLC device may include a function of sequentially delivering all RLC SDUs received before the timer starts to an upper layer if a specific timer expires even with a missing RLC SDU. Further, the in-order delivery function of the NR RLC device may include a function of sequentially delivering all RLC SDUs received so far to an upper layer if a specific timer expires even with a missing RLC SDU.

The

NR RLC

260 and 285 devices may process RLC PDUs in the order received, regardless of sequence number (out-of-order delivery), and deliver them to the NR PDCP 405, 440 devices.

If segments are received, the

NR RLC

260 and 285 devices may receive the segments stored in the buffer or to be received, reconstruct them into one complete RLC PDU, and deliver it to the NR PDCP device.

The NR RLC layer may not include a concatenation function and may perform a function in the NR MAC layer or may replace it with a multiplexing function of the NR MAC layer.

In the above description, out-of-order delivery of the NR RLC device may indicate a function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of order. The out-of-order delivery of the NR RLC devices may include the functions of re-assembling and delivering one original RLC SDU if it is segmented into several RLC SDUs and received. The out-of-order delivery of the NR RLC device may include functions of storing RLC SNs or PDCP SNs of received RLC PDUs, arranging their order, and recording missing RLC PDUs.

The

NR MACs

265 and 280 may be connected to several NR RLC layer devices configured in one UE, and the main functions of the NR MACs may include some of the following functions.

Mapping between logical channels and transport channels

-multiplexing/demultiplexing of MAC SDUs

Scheduling information reporting function

Error correction by HARQ

-priority handling between logical channels of one UE

-prioritization among UEs by dynamic scheduling

-MBMS service identification

-transport format selection

-filling function

The NR PHY layers 260 and 275 may perform operations of channel-coding and modulating upper layer data and generating and transmitting OFDM symbols through a radio channel, or demodulating and channel-decoding OFDM symbols received through a radio channel and delivering them to an upper layer. The NR may determine whether retransmission is required or whether new transmission is performed through scheduling information of a corresponding UE in a Physical Dedicated Control Channel (PDCCH), which is a channel through which downlink/uplink resource allocation is transmitted. This is because asynchronous HARQ is applied in NR. Uplink HARQ ACK/NACK information for downlink data transmission may be transmitted on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) physical channel. PUCCH is typically transmitted in the uplink of PCell to be described, but if the UE supports it, the gNB may additionally transmit to the corresponding UE in the SCell to be described, which is referred to as PUCCH SCell.

Hereinafter, the present disclosure describes an operation of a base station or a terminal in a wireless communication system. In addition to the base station, the base station may be referred to as an "Access Point (AP)", "enodeb (enb)", "5G node", "next generation (G) node b (gnb)", "wireless point", or other terms having the same meaning in the art. According to various embodiments, a base station may be connected with one or more "transmission/reception points (TRPs)". The base station may transmit a downlink signal to the terminal or receive an uplink signal from the terminal via one or more TRPs. Hereinafter, the present disclosure describes, by way of example, a base station as a network node for transmitting radio signals to a terminal. However, the present disclosure is not limited to these terms. The radio signal transmission may include a configuration in which a base station is connected to a TRP and the TRP transmits a radio signal.

In addition to the terminal, the terminal may be referred to as "UE", "mobile station", "subscriber station", "Customer Premises Equipment (CPE)", "remote terminal", "wireless terminal", "electronic equipment", "user equipment" or other terms having technically equivalent meanings.

Communication nodes (e.g., terminals, base stations, and core network entities) according to various embodiments of the present disclosure may operate in an LTE system. Furthermore, communication nodes (e.g., terminals, base stations, and core network entities) according to various embodiments of the present disclosure may operate in an NR system. Further, communication nodes (e.g., terminals, base stations, and core network entities) according to various embodiments of the present disclosure may operate in an LTE system and an NR system. That is, the structures and layer explanations shown in fig. 1A to 2B are exemplary, and any one communication system does not exclude other communication systems.

Referring to fig. 3, an eNB 301 transmits signals in the form of beams for wider coverage or

stronger signals

311, 313, 315, and 317. Therefore, the UE 303 in the cell needs to transmit and receive data using a specific beam (beam # 1313 in this exemplary drawing) transmitted by the eNB.

Meanwhile, the state of the UE is classified into an IDLE mode RRC _ IDLE or a CONNECTED mode RRC _ CONNECTED state depending on whether the UE is CONNECTED to the eNB. Therefore, the eNB does not know the location of the UE in the idle mode state.

If the UE in the idle mode state is to switch to the connected mode state, the UE receives synchronization signal/physical broadcast channel (SS/PBCH) blocks 321, 323, 325, and 327 transmitted by the eNB. The SS/PBCH block may be referred to as an SSB. The SSB may repeat transmission according to a period set by the eNB. Each SSB may include a Primary Synchronization Signal (PSS)341, a Secondary Synchronization Signal (SSS)343, and a Physical Broadcast Channel (PBCH).

A scenario in which SSBs are transmitted for each beam is assumed in this exemplary drawing. For example, it has been assumed that SSB # 0321 is transmitted using beam # 0311, SSB # 1323 is transmitted using beam # 1313, SSB # 2325 is transmitted using beam # 2315, and SSB # 3327 is transmitted using beam # 3317. It is assumed in this exemplary diagram that the idle mode UE is located in beam # 1313, but even if the connected mode UE performs random access, the UE selects an SSB received at the time of random access.

Therefore, UE 303 receives SSB # 1323 transmitted in beam # 1313. Upon receiving the SSB # 1323, the UE 303 may acquire a Physical Cell Identifier (PCI) of the eNB 301 through the PSS and the SSS, and acquire an identifier of a currently received SSB (i.e., #1), a location where the current SSB is received within a 10ms frame, and a System Frame Number (SFN) within the SFN having a period of 10.24 seconds by receiving the PBCH. In addition, the PBCH includes a Master Information Block (MIB) that informs of a location in the MIB for receiving system information block type 1(SIB 1), which SIB1 is used to broadcast more detailed cell configuration information. Upon receiving SIB1, UE 303 may know the total number of SSBs transmitted by eNB 301 and obtain the location of a Physical Random Access Channel (PRACH) opportunity to perform random access (more specifically, transmit a preamble, which is a physical signal specifically designed to achieve uplink synchronization) to transition to a connected mode state (this exemplary figure assumes an allocated scenario every 1 ms: from 330 to 339). Further, based on this information, the UE 303 may obtain the PRACH opportunity and the SSB index mapped in the PRACH opportunity. For example, the exemplary figure assumes a scenario of allocation every 1ms, and a scenario of allocation of 1/2 SSBs per PRACH opportunity (i.e., 2 PRACH opportunities per SSB). Thus, a scenario is shown where two RPACH occasions are allocated per SSB starting from a PRACH opportunity according to SFN. For example,

PRACH opportunities

330 and 331 may be allocated to SSB #0, while

PRACH opportunities

332 and 333 may be allocated to SSB # 1. PRACH opportunities may be configured for all SSBs and may then be allocated back to the first SSB.

Accordingly, the UE 303 identifies the locations of the

PRACH opportunities

332 and 333 of the SSB # 1323, and thus transmits a random access preamble in the earliest PRACH opportunity (e.g., PRACH opportunity 332) of the current point among the

PRACH opportunities

332 and 333 corresponding to the SSB # 1. Since the eNB 301 receives the preamble of the UE 303 in the PRACH occasion 332, it can obtain that the corresponding UE 303 selects the SSB #1 and transmits the preamble. Further, the eNB 301 transmits and receives data through a corresponding beam (e.g., beam # 1313) in a subsequent random access procedure.

Meanwhile, even if the UE in a connected state moves from a current (source) eNB to a destination (target) eNB due to handover, the UE may perform random access at the target eNB, and the UE may perform operations of selecting an SSB and transmitting random access. Further, in handover, a handover command may be sent to the UE to move from the source eNB to the target eNB, where the message may be assigned a corresponding UE-specific random access preamble identifier for each SSB of the target eNB for random access by the target eNB. At this time, the eNB may not allocate the dedicated random access preamble identifier to all beams (depending on the current location of the UE), and accordingly, the dedicated random access preamble may not be allocated to some SSBs (e.g., the dedicated random access preamble is allocated only to beam # 2315 and beam # 3317). If the dedicated random access preamble is not allocated to the SSB selected by the UE for preamble transmission, the UE performs random access by randomly selecting a contention-based random access preamble. For example, it is assumed in the figure that the UE 303 is initially located within the coverage of the beam #1 and performs random access, but fails in random access. By moving, the UE 303 may be located within the coverage of beam # 3317. The UE 303 may transmit the dedicated random access preamble based on SSB # 3327 transmitted through beam # 3317. That is, if preamble retransmission occurs, a contention-based random access procedure and a non-contention-based or contention-free random access procedure may coexist in one random access procedure depending on whether a dedicated random access preamble is allocated to a selected SSB in each preamble transmission.

Fig. 4 illustrates an example of a random access procedure in a wireless communication system, in accordance with various embodiments of the present disclosure. The figure illustrates a contention-based 4-step random access procedure performed by a UE in the case of initial access, re-access, handover, or other random access to a gNB.

Referring to fig. 4, in step 411, UE 401 may transmit a random access preamble to gNB 403. The random access preamble may be referred to as a Message (MSG) 1. To access the gNB 403, the UE 401 selects a PRACH opportunity according to the above-described fig. 3, and transmits a random access preamble to a corresponding PRACH based on the selected PRACH opportunity 411. One or more UEs may simultaneously transmit a random access preamble through PRACH resources. The PRACH resource may cover one subframe or may use only some symbols within one subframe. The PRACH resource information is included in the system information broadcast by the gNB 403, so the UE 401 can obtain time-frequency resources for transmitting the preamble. Further, the random access preamble is a specific sequence specifically designed so that it can be received even before being completely synchronized with the gNB 403, there may be a plurality of preamble identifiers (indexes) as defined in the standard, and if there are a plurality of preamble identifiers, the random access preamble transmitted by the UE 401 may be randomly selected by the UE or a specific preamble designated by the gNB 403.

In step 421, the gNB 403 may send a Random Access Response (RAR) to the UE 401. The RAR may be referred to as MSG 2. If gNB 403 receives the random access preamble of step 411, gNB 403 may send a RAR message for it to UE 401. The RAR message may include identifier information of the preamble used in step 411. For example, if a plurality of UEs attempt random access by transmitting different preambles in step 411, the RAR messages may respectively include responses to the preambles. Preamble identifier information included in the RAR message is transmitted to inform to which preamble the corresponding response is a response message.

Further, the RAR message may include uplink transmission timing correction information, uplink resource allocation information to be used in step 431, and temporary UE identifier information (e.g., temporary cell radio network temporary identifier (TC-RNTI)). The uplink resource allocation information included in each response of each preamble is detailed information of resources to be used by the UE in step 431 and includes a physical location and size of the resources, a Modulation and Coding Scheme (MCS) used in transmission, transmission power adjustment information, and the like. If the UE transmitting the preamble performs initial access, the UE does not have an identifier allocated by the gNB for communication with the gNB, and thus the temporary UE identifier information is a value transmitted for use thereof.

Meanwhile, the RAR message may include not only a response to each preamble but also optionally a Backoff Indicator (BI). The backoff indicator is a value that is transmitted if random access is not successfully performed and a random access preamble needs to be retransmitted, to randomly delay transmission according to the value of the backoff indicator without immediately retransmitting the preamble. In more detail, if the UE does not correctly receive the RAR, or if contention resolution to be described is not successfully performed, the UE needs to retransmit the random access preamble. At this time, the value indicated by the backoff indicator may indicate the index values of table 1 below, and the UE may select a random value from 0 to the value indicated by the index value. The UE retransmits the random access preamble after a time corresponding to the selected value. For example, if the gNB indicates 5 (i.e., 60ms) as the BI value and the UE randomly selects a value of 23ms between 0 and 60ms, the UE stores the selected value in the variable PREAMBLE _ BACKOFF and the UE performs a procedure of retransmitting a PREAMBLE after 23 ms. If the backoff indicator is not transmitted, if the random access is not successfully performed and retransmission of the random access preamble is required, the UE immediately transmits the random access preamble.

[ Table 1]

Index	Backoff parameter value (ms)
		0	5
1	10
		2	20
3	30
		4	40
5	60
		6	80
7	120
		8	160
9	240
		10	320
11	480
		12	960
13	1920
		14	Retention
15	Retention

The RAR message should be sent within a specified duration starting after a specified time after the preamble is sent and this duration may be referred to as the "RAR window 423". The RAR window starts at a timing after a specified time from the start of the first preamble transmission. The specified time may have a value of a subframe unit (1ms) or less. Further, the length of the RAR window may be a specified value configured per PRACH resource or set of one or more PRACH resources within the system information message broadcast by the gNB.

Meanwhile, if the RAR message is transmitted, the gNB schedules the corresponding RAR message on the PDCCH and scrambles the corresponding scheduling information using a random access radio network temporary identifier (RA-RNTI). The RA-RNTI may be determined based on PRACH resources used to transmit the random access preamble. The UE transmitting the random access preamble in a specific PRACH resource attempts PDCCH reception based on the corresponding RA-RNTI and determines whether there is a corresponding RAR message. That is, if the RAR message is a response to the random access preamble transmitted by the UE in step 411 as shown in the figure, the RA-RANTI for RAR message scheduling information includes information of the random access preamble transmission of step 411. For this, the RA-RNTI can be calculated by the following equation.

RA-RNTI＝1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id

In this case, s _ id is an index corresponding to the first OFDM symbol where the random access preamble transmission of step 411 starts, and has a value of 0 ≦ s _ id <14 (i.e., the maximum number of OFDM in one slot). In addition, t _ id is an index of the first slot corresponding to the start of random access preamble transmission of step 411, and has a value of 0 ≦ t _ id <80 (i.e., the maximum number of slots in 10ms of one system frame in consideration of PRACH subcarrier spacing (SCS)). Furthermore, f _ id indicates which PRACH resource (i.e., PRACH opportunity) on that frequency the random access preamble of step 411 was transmitted, and has a value of 0 ≦ f _ id <8 (i.e., the maximum number of PRACH on that frequency in the same time). Ul _ carrier _ id is an indicator for distinguishing between two carriers if they are used as the uplink of one cell. The two carriers include a Normal Uplink (NUL) and a Secondary Uplink (SUL). In NUL, ul _ carrier _ id may have a value of 0, and in SUL, ul _ carrier _ id may have a value of 1.

In step 431, UE 401 may perform a scheduled transmission to the gNB 403. Here, the scheduled transmission may include an identity of the UE 401 (i.e., a UE identity), and the transmitted message may be referred to as MSG 3. The message may be sent over the PUSCH. A UE receiving the RAR message may transmit different messages according to the aforementioned various purposes in the resources allocated to the RAR message. For example, the Msg3 sent by the UE may be a RRCSetupRequest message, which is a RRC layer message in the initial access, a rrcreestablstringrequest message in the re-access, and a rrcreeconfigurationcomplete message in the handover. Alternatively, a Buffer Status Report (BSR) message for the resource request may be transmitted.

In step 441, the gNB 403 may send a contention resolution message to the UE 401. In the initial access (i.e., if Msg3 does not include the gNB identifier information previously assigned to UE 401, etc.), UE 401 may receive a contention resolution message from gNB 403. The contention resolution message includes contents transmitted by the UE as is in Msg3, and the gNB 403 can inform which UE the response is for even if a plurality of UEs select the same preamble in step 411.

Fig. 5 illustrates an example of a bandwidth part (BWP) operation in a wireless communication system according to various embodiments of the present disclosure. BWP may be used in an NR communication system so that one UE performs communication using only some frequency bandwidths among system bandwidths used by one cell. BWP is used to reduce terminal manufacturing cost or save terminal power. BWP may be set by the gNB only for UEs supporting it.

Referring to fig. 5, there are three main BWP operation scenarios.

The first scenario applies BWP for UEs that support only a bandwidth 510 narrower than the system bandwidth 505 used by one cell. To reduce manufacturing costs, specific UEs may be developed to support limited frequency bandwidths. The UE needs to report to the base station that only a limited bandwidth is supported, so the gNB configures BWP of the maximum bandwidth supported by the UE or less.

The second scenario applies BWP for terminal power saving. For example, one UE performs communication using the entire system bandwidth 515 or a partial bandwidth (e.g., the second BWP 520) used by one cell, but the communication base station may set a narrower bandwidth (e.g., the first BWP 525) for power saving.

A third scenario applies a single BWP corresponding to different parameter sets. Parameter sets mean that the physical layer configuration is diversified to achieve optimal data transmission according to various service requirements. For example, an Orthogonal Frequency Division Multiple Access (OFDMA) structure including a plurality of subcarriers may variably adjust the SCS according to a designated requirement. One UE may communicate based on multiple parameter sets (numerology) simultaneously. At this time, since the physical layer configuration corresponding to each parameter set may be different, it is desirable to divide and operate each parameter set into separate first and second BWPs 530 and 535.

Meanwhile, if the UE transitions from the RRC _ IDLE state or the RRC _ INACTIVE state to the RRC _ CONNECTED state, the BWP for the UE to attempt to access the network is referred to as an initial BWP. The UE may receive additional BWP from the gNB if the UE successfully accesses the gNB and enters the RRC _ CONNECTED state. In this case, one of BWPs additionally set by the gNB may be set as a default BWP to be described, and if the default BWP is not separately set, the initial BWP becomes the default BWP.

Further, in the above scenario, the terminal may be configured with a plurality of BWPs, and then may activate a specific BWP among the BWPs set by the gNB. For example, a scenario where the UE may receive the first BWP 530 and the second BWP 535 and the gNB activates one of the two BWPs in the third scenario is possible. Accordingly, in the above scenario, the UE may transmit and receive data through active BWP for downlink and uplink.

If multiple BWPs are set, the UE may change the active BWP, which is called BWP transition. This may be performed by allocating resources to BWPs to be converted in the PDCCH transmitted by the gNB.

In the unlicensed band, a scene using the same parameter set in the third scene may be operated. For example, since a device such as a wireless Local Area Network (LAN) operates in a bandwidth of 20MHz in an unlicensed band, a base station may configure several BWPs corresponding to 20MHz, such as the first BWP 530 and the second BWP 535 in the figure, and move each BWP for a UE according to a congestion level of the unlicensed band.

In a second scenario, the UE may change/switch BWP to a default BWP (e.g., second BWP 525), for example, if the communication is not scheduled on a wide bandwidth (e.g., system bandwidth 515, first BWP 520) in the activated PCell or SCell and within a time BWP-InactivityTimer set by the gNB in the respective cell. Thus, the previously used BWP is deactivated and the default BWP is activated. Alternatively, if the communication is on a particular bandwidth (e.g., second BWP 525) and is indicated by the gNB over the PDCCH as being scheduled to another BWP, the UE moves to the indicated BWP (e.g., first BWP 520), where the existing BWP is deactivated and the indicated BWP is activated. At this time, the active (i.e., currently used) BWP may be referred to as an active BWP.

Meanwhile, the NR communication system supports a wideband (e.g., 100MHz) frequency bandwidth, but not all UEs need to support the wideband. For example, a wearable device such as a smart watch may only require sufficient bandwidth for communication. Therefore, the necessity arises for a UE simplified only with the basic functionality of the requirements of existing NR UEs, which may be referred to as "NR-lite" UEs. For example, NR-lite UEs may support a smaller bandwidth (e.g., 10MHz or 20MHz) than that of existing NR UEs, and SCS may also support only basic values, such as 15 kHz. Furthermore, the NR-lite UE may be limited to 20Mbps, etc., in terms of maximum supported data rate. Hereinafter, a procedure of the NR-lite UE accessing the network is described in fig. 6 and 7. Hereinafter, various embodiments of the present disclosure are described by referring to a UE having limited performance as an NR-lite UE, but terms such as "light UE", "small UE", "thin UE", "low cost UE", "low power UE", "limited BWP UE", "reduced BWP UE", "IoT device" may be used interchangeably instead of the term NR-lite UE.

Fig. 6 illustrates an example of an initial access procedure of an NR-lite UE in a wireless communication system according to various embodiments of the present disclosure. The NR-lite UE may send or receive messages to access the gNB.

Referring to fig. 6, in step 611, an NR-lite UE may camp on a cell. The NR-lite UE may be in an IDLE mode RRC IDLE state without being connected to the gNB. The NR-lite UE may camp on the gNB that detected the signal to receive data transmitted from the network.

In step 613, the NR-lite UE may receive the SS/PBCH block from the gNB. In step 611, the UE may receive an SS/PBCH block transmitted from the gNB of the camped cell. The description of the SS/PBCH block of fig. 3 may be applied to the description of the SS/PBCH block in the same or similar manner. The SS/PBCH block may include MIB of PBCH in addition to synchronization signals of PSS and SSS. The NR-lite UE may obtain the MIB from the PBCH. For example, the structure of the MIB may be configured as shown in [ table 2] below.

[ Table 2]

In step 615, the NR-lite UE may determine to access the corresponding cell. In step 611, the NR-lite UE may determine whether to access the camped cell based on the MIB. That is, the NR-lite UE may primarily determine whether a cell is accessible by the NR-lite UE using information included in the MIB. Hereinafter, a method of an NR-lite UE determining an accessible cell according to various embodiments of the present disclosure is described.

In some embodiments, the NR-lite UE may determine whether a corresponding cell is accessible based on subcarriersspacingmmon in the MIB. If the NR-lite UE supports only SCS of 15kHz, the NR-lite UE may determine whether the subCarrier SpacingCommon value is SCS15 or 60. If the subanticierspacincommon value is SCS30 or 120, the NR-lite UE may determine that the SCS, such as SIB1, is 30kHz (or 120kHz) and determine that access to the corresponding cell is prohibited. Next, the NR-lite UE may attempt camping by searching for another cell within the same carrier frequency. Further, if it is determined that all cells of the corresponding carrier frequency do not support the NR-lite UE, or if it is assumed that all cells do not support the NR-lite UE, the NR-lite UE may stop cell search of the corresponding carrier frequency and attempt camping by searching another cell of another carrier frequency.

Furthermore, even if the SCS value supports 15kHz, the NR-lite UE can recognize the pdcch-ConfigSIB1 and determine whether additional access is possible. The PDCCH-ConfigSIB1 indicates a resource set (which may be referred to as a control resource set (CORESET)) for monitoring the PDCCH of the scheduled SIB 1. If the bandwidth of CORESET is greater than the bandwidth supported by the NR-lite UE, the NR-lite UE may not be able to monitor all SIBs 1 to determine that access to the corresponding cell is barred. The NR-lite UE may attempt to camp on by searching for another cell within the same carrier frequency. Further, as in the subanticierspacingmommon described above, the NR-lite UE may determine that the corresponding carrier frequencies are all barred, stop cell search of the corresponding carrier frequencies, and attempt camping by searching another cell of another carrier frequency.

In some embodiments, the NR-lite UE may determine whether the NR-lite UE is accessed based on the intrafreq reselection value. According to one embodiment, if all the above conditions (e.g., subcarriersspacingmmon condition, pdcch-ConfigSIB1 condition) are passed, the NR-lite UE may determine whether the NR-lite UE can access the corresponding cell based on the intrafreq reselection value. For example, the values of the cellBarred field and the intrafreq selection field may be configured as shown in [ table 3] below, according to the current NR standard.

[ Table 3]

cellBarred	intraFreqReselection
		barred	allowed
barred	notAllowed
		notBarred	Not used

That is, if cellBarred is indicated as notBarred, the intrafreq selection value is not used. Thus, in some embodiments of the present disclosure, if cellBarred is indicated as notBarred, the gNB may explicitly inform that the corresponding cell of the gNB is a cell supporting NR-lite UEs by setting the intrafreq reselection value to allowed. In contrast, by setting cellBarred to indicate notBarred and setting intraFreqReselection value to notAllowed, the gNB may explicitly inform that the corresponding cell of the gNB is a cell that does not support NR-lite UEs.

In some embodiments, the NR-lite UE may explicitly inform the NR-lite capable cells by utilizing the remaining 1-bit spare field instead of the intrafreq reselection field.

In fig. 6, it is described that the NR-lite UE determines whether a corresponding cell is a cell accessible by the NR-lite UE based on the MIB, and performs a subsequent operation (e.g., an SIB1 reception operation of step 617) on the assumption that the cell is accessible, but the present disclosure is not limited thereto. According to an embodiment, the NR-lite UE may determine the cell where the NR-lite UE is camped, i.e. the cell providing the MIB is a cell not accessible to the NR-lite UE. That is, an operation in which the NR-lite UE determines that the corresponding cell does not support the NR-lite UE based on the MIB may also be understood as an embodiment of the present disclosure.

In step 617, the NR-lite UE may receive the SIB 1. If it is determined that the cell is not barred by reading the MIB (i.e., decoding the MIB) through the above procedure, the NR-lite UE may receive the SIB1 based on the aforementioned pdcch-ConfigSIB1 information. The SIB1 may include serving cell information (e.g., Servingcellcommon). The serving cell information may include downlink BWP information and uplink BWP information. The downlink BWP and the uplink BWP may be used to perform a subsequent transmission/reception process.

In step 619, the UE may acquire BWP information of the NR-lite UE. Since the bandwidth of the initial Downlink (DL) BWP is the same as the bandwidth (Coreset 0 bandwidth) notified with the pdcch-ConfigSIB1 in the NR, a separate initial DL BWP for the NR-lite UE is not required. However, in some embodiments, for subsequent operation of NR-lite UEs, the gNB may need to provide separate initial DL BWP information to the NR-lite UEs. In the initial Uplink (UL) BWP, the NR-lite UE may not be able to recognize the bandwidth using only the MIB information of step 613. Thus, the NR-lite UE can recognize the initial UL BWP through information transmitted in the SIB 1.

In the detailed information of the initial UL BWP, which is information transmitted in the SIB1, if the bandwidth of the initial UL BWP is greater than the bandwidth of a cell supportable by the NR-Lite UE, the UE may recognize whether there is a separate initial UL BWP for the NR-Lite UE (may be referred to as initializonbwp 2 or initializonbwp-NR-Lite).

If the bandwidth of the initial UL BWP is greater than the bandwidth of the cell supportable by the NR-lite UE and there is no separate initial UL BWP, the NR-lite UE considers that the corresponding cell is barred and attempts camping by searching for another cell within the same frequency. Alternatively, the NR-lite UE may assume that all cells of the corresponding frequency do not support the NR-lite UE, stop cell search of the corresponding carrier frequency, and attempt camping by searching another cell of another carrier frequency.

Alternatively, if a separate initial UL BWP is not defined, if the bandwidth of the initial UL BWP is greater than that of a cell supportable by the NR-lite UE, the NR-lite UE considers that the corresponding cell is barred and attempts camping by searching for another cell of the same carrier frequency. Alternatively, assuming that all cells of the corresponding carrier frequency do not support the NR-lite UE, the NR-lite UE may stop cell search of the corresponding carrier frequency and attempt camping by searching another cell of another carrier frequency.

If a separate initial DL/UL BWP is defined, the gNB may inform NR-lite UEs in the cell of all initialDownlinkBWP2, initialUppllinkBWP 2, PDCCH-ConfigCommon2(coreset and searchspace), etc. In addition, the gNB may separately notify the NR-lite UE of BCCH configuration information for SIB transmission and PCCH configuration information for paging transmission. At this time, according to an embodiment, initialdown bwp2 may be formed as a subset of initialdown bwp, only locationandbandwith information is different, and the remaining parameters (subcarrierspating, pdcch-ConfigCommon, etc.) may be used jointly between NR-lite UE and general UE (i.e., UE other than NR-lite UE). That is, only locationandblockwidth information is signaled in initialDownlinkBWP2, and the remaining parameters utilize information in the existing initialdwlnp, and thus signaling overhead can be reduced. The same applies to initialUplinkBWP. For example, initialUplinkBWP2 is formed as a subset of initialUplinkBWPs, only locationAndBandwidth information is different, and the remaining parameters (Subcarrierspacing, pdcch-ConfigCommon, etc.) may be used jointly by NR-lite UEs and normal UEs (i.e., UEs other than NR-lite UEs).

In step 621, the NR-lite UE may receive NR-lite UE related system information. Here, the NR-lite UE-related system information may indicate system information (e.g., SIB2, SIB3, SIB4) received after the SIB1, and include information specific to the NR-lite UE. If the NR-lite UE determines whether access is possible through the MIB and the SIB1 and determines that the corresponding cell does not prohibit the NR-lite UE, the UE may receive other SIB information from the corresponding cell. In some embodiments, other SIB information, i.e. NR-lite UE related system information, separately indicates which cells within frequency (same frequency) or inter frequency (different frequencies) support NR-lite UEs or do not support NR-lite UEs, and thus can be used to reselect cells for NR-lite UEs if the UE reselects cells or switches due to a change in signal strength or a change in channel state. According to an embodiment, the NR-lite UE may perform intra-frequency measurements or inter-frequency measurements. In this way, cells that do not support NR-lite UEs among neighboring cells of system information can be excluded from the measurement target. Further, according to an embodiment, if a measurement report is transmitted, the NR-lite UE may exclude cells that do not support the NR-lite UE from the reporting target. Further, according to the embodiment, if the UE performs measurement according to the measurement configuration, it may exclude a cell that does not support the NR-lite UE from the measurement object.

Step 621 is shown to explain system information of the NR-lite UE, but the present disclosure is not limited thereto. According to embodiments, the system information after the SIB1 may not include separate information for NR-lite UEs. That is, step 621 may be omitted.

In step 623, the NR-lite UE may receive the paging. The NR-lite UE may receive paging if the NR-lite UE is in IDLE mode (e.g., RRC _ IDLE). Next, the NR-lite UE may transition back to the CONNECTED mode (e.g., RRC _ CONNECTED) by receiving a paging message from the corresponding cell. The NR-lite UE can access the network through a random access procedure and recognize whether there is downlink data from the network. The above description of fig. 4 or the process of fig. 7 to be described may be applied to the random access procedure in the same or similar manner. Alternatively, in accordance with an embodiment, to reduce signaling overhead, the random access procedure may employ a 2-step RACH procedure, including message a (MSG a) transmission instead of MSG1 and MSG3 of the 4-step RACH procedure, and MSG B transmission instead of MSG2 and MSG 4 of the 4-step RACH procedure.

Fig. 6 shows that step 623 is performed after step 621, but the present disclosure is not limited thereto. The NR-lite UE may receive the page if the NR-lite UE is in idle mode.

Fig. 6 describes a process in which an NR-lite UE receives system information (e.g., MIB, SIB1) from a cell and determines whether the cell supports the NR-lite UE based on the system information. However, according to an embodiment, the cell of the present disclosure may support normal UEs as well as NR-lite UEs. Therefore, even if other general UEs than the NR-lite UE receive information (e.g., initialldownlinkbwp 2) for the NR-lite UE, ignoring or discarding the information may be understood as an embodiment of the present disclosure.

The UE receiving the system information required for access may transition to the RRC connected mode through a random access procedure. Hereinafter, an embodiment of performing a random access procedure for an NR-lite UE will be described in fig. 7.

Fig. 7 illustrates an example of a random access procedure for NR-lite UEs in a wireless communication system, according to various embodiments of the present disclosure.

Referring to fig. 7, in step 725, the NR-lite UE may initiate RRC connection setup. For example, if the UE receives a paging message from the cell and needs to receive downlink data, or if uplink data to be transmitted occurs, it may determine to transition to the RRC _ CONNECTED mode for corresponding data transmission/reception. The NR-lite UE may perform random access. At this time, if the NR-lite UE and the general NR UE perform random access using the same initial DL BWP and initial UL BWP and the same random access parameters, the UE may operate as follows.

In step 731, the NR-lite UE may send MSG1 to the gNB. The NR-lite UE may transmit a random access preamble.

In step 733, the gNB may transmit MSG2 to the NR-lite UE. The gNB may send RARs to the NR-lite UEs. The NR-lite UE may receive the RAR. The NR-lite UE may acquire uplink resources for MSG3 transmission from the RAR from the gNB.

In step 735, the NR-lite UE may determine indication information. The NR-lite UE may determine the indication information according to whether it is necessary to inform the gNB whether a UE performing a random access procedure is an NR-lite UE. For example, since the NR-lite UE is limited in terms of data rate of transmission and reception, it is necessary to notify the NR-lite UE in this random access step before the gNB transmits capability information of the UE to not randomly transmit data to the UE. Accordingly, the NR-lite UE may determine indication information informing the NR-lite UE.

The indication information may be expressed in various ways. In some embodiments, the NR-lite UE may select the following Logical Channel Identifier (LCID) according to a type of message to be transmitted in MSG3, and transmit MSG3 based on the selected LCID.

LCID A used by NR-lite UEs (i.e., UEs limited in BW and maximum TB size) to send 48-bit Common Control Channel (CCCH) Service Data Unit (SDU) messages.

LCID B for transmitting 48 bits of CCCH SDU information.

LCID C for transmitting 64-bit CCCH SDU messages.

(A, B and C are designated integer values defined by the standard and labeled A, B and C for ease of description).

If the CCCH SDU to be transmitted in MSG3 is an RRCSetupRequest, the UE selects and reports one of LCID a and LCID B, and if the UE is an NR-lite UE, LCID a is selected.

Further, if the CCCH SDU to be transmitted in MSG3 is RRCResumeRequest, the UE selects and reports one of LCID B and LCID C. The RRCResumeRequest message is a message for transitioning from the RRC _ INACTIVE state to the RRC _ CONNECTED state, and does not need to be re-notified to the NR-lite UE, because the gNB transitions to the RRC _ CONNECTED state once and notifies the NR-lite UE, and thus the NR-lite terminal determines the LCID only according to the size of the RRCResumeRequest message.

Further, if the CCCH SDU to be transmitted in MSG3 is rrcreestablstrimentrequest, the UE selects and reports LCID B. This is for the UE in RRC _ CONNECTED state to recover from the degradation of radio channel conditions, and because it is known that the gNB of the NR-lite UE does not need to re-inform the NR-lite UE, and the rrcreestablishrequest has a single size of 48 bits. Meanwhile, according to the embodiment, regardless of whether it is determined to notify the NR-lite UE, if the UE performing the random access is the NR-lite UE, the NR-lite UE may always use LCID a in CCCH transmission.

In step 737, the NR-lite UE may transmit MSG3 to the gNB. The NR-lite UE may generate MSG3 based on the indication information determined in step 735 and transmit MSG3 to the gNB.

In step 739, the gNB may transmit MSG 4 to the NR-lite UE. The NR-lite UE may transmit MSG3 and receive a response message (i.e., RRC setup/RRC response/RRC maintenance) for identifying MSG 4, which is correctly transmitted by the corresponding MSG3, and an RRC message transmitted in MSG 3.

The present disclosure illustrates a scenario in which the LCID included in MSG3 informs the UE that the NR-lite UE is, but the present disclosure is not limited thereto. That is, for example, a method of explicitly informing by using a spare bit of an RRC message included in MSG3 in addition to an LCID may also be considered. Further, a method of explicitly notifying the NR-lite UE through a separate value in the estabilishment cause of the RRCSetupRequest message may also be considered.

Meanwhile, unlike the above description, if different initial UL BWP initialldownlinkbwps 2 are set at the NR-lite UE, or if the same initial DL BWP and initial UL BWP are used but the random access related parameters are set differently, the NR-lite UE may not need to separately inform that the corresponding UE is the NR-lite UE in the MSG 3. For example, each uplink transmission sent by the UE may be an initial UL BWP separate from the transmissions of the normal UE, or the random access resource may be a PRACH resource separate from the transmissions of the normal UE. Thus, the gNB may obtain that the corresponding UE is an NR-lite UE by receiving only MSG 1.

Instead, the gNB may set the separate search space of the NR-lite UE with initialldownlinkbwp 2 for MSG2 reception. Alternatively, the gNB may distinguish the preamble transmission of MSG1 and set the search space in initialdown linkbwp 2. In this case, since the random access preamble is different even if the NR-lite UE receives the MSG2, the NR-lite UE can receive a response to the random access preamble for the NR-lite UE without being confused with a response to a random access preamble of a general UE.

Further, according to embodiments, the gNB may distinguish between NR-lite UEs and normal UEs by adding an offset for NR-lite UEs to the RA-RNTI that scrambles the PDCCH used in the MSG2 transmission. The NR-lite UE may identify whether the received RAR is a response to a random access preamble of the NR-lite UE by applying a specified offset to the RA-RNTI and receiving the RAR. That is, the NR-lite UE may acquire a new identifier by applying a specified offset to the RA-RNTI. The NR-lite UE may identify whether the received RAR is a response to the random access preamble of the NR-lite UE by identifying whether the RAR is masked by a new identifier.

Furthermore, according to embodiments, the gNB may also consider a method for including an indicator explicitly informing that the scheduling is for an NR-lite UE into information included in a PDCCH used in MSG2 transmission. The NR-lite UE may obtain an indicator by decoding the PDCCH and identify from the indicator whether the received RAR is a response to a random access preamble of the NR-lite UE.

Fig. 8 illustrates an example of a capability information transmission procedure of an NR-lite UE in a wireless communication system according to various embodiments of the present disclosure. The capability information of the NR-lite UE is UE capability information and may include constraints on the NR-lite UE.

Referring to fig. 8, the gNB may transmit a UE capability query message to the NR-lite UE in step 841. If the NR-lite UE never accesses the network and the core network (MME of LTE or AMF of NR) has no capability information of the UE, the core network may order the gNB to receive the UE capability information. Accordingly, the gNB may transmit a UE capability query message requesting capability information to the NR-lite UE.

At step 843, the NR-lite UE may send UE capability information to the gNB. The NR-lite UE may transmit the capability information to the gNB if a request to transmit the UE capability information is received from the gNB.

The UE capability information of the NR-lite UE may be configured in various ways. In some embodiments, the UE capability information of the NR-lite UE may include 1-bit information indicating the characteristics of the NR-lite UE described above (limited SCS/BW/Transport Block (TB) size) (e.g., NR-lite is set to { supported }). For example, the 1-bit information may indicate that the UE transmitting the UE capability information is an NR-lite UE, the SCS of the NR-lite UE is a specified value (e.g., 15kHz), the bandwidth of the NR-lite UE is a specified value (e.g., 10MHz), and the maximum value of the TB size of the NR-lite UE (e.g., 5000 bits). If an NR-lite UE is supported, the gNB can configure system information according to specified values and perform scheduling.

In some other embodiments, the UE capability information of the NR-lite UE may include at least one Information Element (IE). The at least one IE may be an IE identically existing in the UE capability information of the normal UE. According to the value indicated by the at least one IE, the gNB may determine that the UE transmitting the capability information is an NR-lite UE. In other words, the NR-lite UE may indirectly indicate that the UE transmitting the UE capability information is the NR-lite UE through the at least one IE. For example, the UE may be indicated to be an NR-lite UE based on at least one or a combination of a supported SCS value, a supported band value, and BWP-related capability information included in the UE capability information. As another example, the UE may be indicated to be an NR-lite UE by a spare value (spare 1) of an IE (e.g., RAT-Type) included in the UE capability information.

In order to handover a corresponding UE from a current gNB to another gNB, the gNB may identify whether the UE requiring handover is an NR-lite UE by using the capability information. If the UE is an NR-lite UE, the gbb may initiate handover only if the target gbb supports NR-lite UEs.

The UE capability query procedure has been illustrated in fig. 8, but the capability information transmission procedure of the present disclosure is not limited thereto. According to the embodiment, the operation of the NR-lite UE transmitting the capability information of step 843 may also be understood as an embodiment of the present disclosure without the step 841 of the gNB transmitting the query message.

Fig. 9 illustrates an operational flow of an NR-lite UE for accessing a network in a wireless communication system, according to various embodiments of the present disclosure.

Referring to fig. 9, the NR-lite UE may obtain the MIB from the SS/PBCH block in step 901. The figure may assume that the NR-lite UE is in an IDLE mode RRC _ IDLE state, is not connected to the gNB, and may camp on the gNB that detected the signal to receive data transmitted from the network. In other words, the NR-lite UE may camp on any cell to receive system information. The NR-lite UE may attempt to receive the SS/PBCH block on any carrier frequency. The NR-lite UE may receive the SS/PBCH block of the cell. In addition to the synchronization signals, the SS/PBCH block may include MIB transmitted in accordance with PBCH. The NR-lite UE may acquire the MIB of the corresponding cell. The structure of the MIB may be configured as shown in [ table 4 ].

[ Table 4]

At this time, the NR-lite UE primarily determines whether the NR-lite UE can access the cell using information included in the MIB. The determination method is as follows.

The NR-lite UE first determines whether it can be accessed using subanticierspacingmmon of the MIB. That is, if only 15kHz is supported for SCS, the NR-lite UE may determine whether the subanticierspacincommon value is SCS15 or 60, consider access to the corresponding cell to be barred by determining that the subsequent SCS, such as SIB1, is 30kHz for SCS30 or 120, and attempt camping by searching for another cell within the same carrier frequency. In doing so, the NR-lite UE may determine that all cells of the corresponding carrier frequency do not support the NR-lite UE, or may stop cell search in the corresponding carrier frequency by assuming this. Next, the NR-lite UE may attempt camping by searching for another cell of another frequency.

Furthermore, even if the SCS value supports 15kHz, the NR-lite UE may additionally determine whether a corresponding cell is accessible based on other information in the MIB. For example, the NR-lite UE recognizes the pdcch-ConfigSIB1 and determines whether additional access is possible. The PDCCH-ConfigSIB1 informs a set of resources for monitoring the PDCCH scheduled for SIB 1. (this is called CORESET.) if the bandwidth of CORESET is greater than the bandwidth supported by NR-lite UEs, a UE that may not be able to monitor each SIB1 may consider access to the corresponding cell to be barred and attempt to camp on by searching for another cell within the same carrier frequency. In the same manner as the subbcarriersspacingmmon described above, if it is determined that the corresponding carrier frequencies are all prohibited, the NR-lite UE may stop cell search of the corresponding carrier frequency and attempt camping by searching another cell of another carrier frequency.

Meanwhile, the foregoing embodiment describes the condition of subcerrirSpacingCommon (hereinafter, first condition) and the condition of pdcch-ConfigSIB1 (hereinafter, second condition), and describes that the first condition is satisfied and then it is determined whether the second condition is satisfied, but the present disclosure is not limited thereto. According to an embodiment, the NR-lite UE may determine whether the corresponding cell supports the NR-lite UE based only on the second condition. Further, according to the embodiment, regardless of the determination order of the first condition and the second condition, if both conditions are satisfied, the NR-lite UE may determine that the corresponding cell supports the NR-lite UE. Also, other field values in the system information may be additionally used to determine whether the corresponding cell supports the NR-lite UE, in addition to the above-described first and second conditions.

The NR-lite UE can determine whether the NR-lite UE accesses the corresponding cell by additionally using the existing intrafreq reselection value. That is, if the above first and second conditions are satisfied, the NR-lite UE may determine whether the NR-lite UE accesses a corresponding cell. According to the current NR standard, the values of the cellBarred field and intrafreq reselection field may be set as shown in table 5 below.

[ Table 5]

That is, if cellBarred is indicated as notBarred, the intrafreqReselection value is not used. Therefore, if cellBarred is indicated as notBarred, the present invention can set the intraFreqReselection value to allowed, thereby informing that the corresponding cell is a cell supporting NR-lite UE. In contrast, cellBarred may indicate notBarred, and the intraFreqReselection value may be set to notallelled, thereby informing that the corresponding cell is a cell that does not support NR-lite UE.

According to another embodiment, the NR-lite UE may determine whether the corresponding cell supports the NR-lite UE based on the intrafreq reselection value, independently of the first and second conditions as described above.

Alternatively, the gNB may inform that the corresponding cell is a cell supporting NR-lite by using the remaining 1-bit spare field instead of the intrafreq reselection field. The conditions for determining whether the cell attempting to access can serve the NR-lite UE based on the MIB have been described in step 911. Although the above conditions have been continuously described, modifications may be made within a range that is easily understood by those skilled in the art. For example, if any one of the above values indicates that the corresponding cell supports NR-lite UEs, the NR-lite UEs may determine that the corresponding cell supports NR-lite UEs.

In step 903, the NR-lite UE may receive the SIB 1. If the NR-lite UE decodes the MIB and determines that the corresponding cell is not barred, it may receive SIB1 based on the MIB's pdcch-ConfigSIB1 information.

According to an embodiment, the same bandwidth of initial DL BWP as that notified by the pdcch-ConfigSIB1 (Coreset 0 bandwidth) may not require a separate initial DL BWP for NR-lite UEs in NR. In this case, the NR-lite UE may share the initial DL BWP value with the normal UE. However, the subsequent operation of the NR-lite UE may nonetheless require separate initial DL BWP information, depending on the options to be described. According to another embodiment, the gNB may provide bandwidth information (e.g., initial DL BWP2) specific to the NR-lite UE through SIB 1.

In step 905, the NR-lite UE may acquire initial BWP information of the NR-lite UE. The initial BWP information of the NR-lite UE may be the same as that of the general UE or may be BWP information separately configured by the gNB.

In the initial UL BWP, the bandwidth may not be identified using only information of the MIB. Thus, the NR-lite UE can recognize the initial UL BWP through information transmitted in the SIB 1.

The NR-lite UE may determine whether the corresponding cell serves NR-lite (i.e., supports NR-lite UEs) based on the initial UL BWP. In some embodiments, in the detailed information of the initial UL BWP, which is information transmitted in the SIB1, if the bandwidth of the initial UL BWP is greater than a cell supportable by the NR-Lite UE, the UE recognizes whether there is a separate initial UL BWP (initialuplinkbpp 2/initialuppinr-Lite) for the NR-Lite UE. If the bandwidth of the initial UL BWP is greater than the cells supportable by the NR-lite UE and there is no separate initial UL BWP, the NR-lite UE considers the corresponding cell to be barred and attempts camping by searching for another cell within the same carrier frequency. The NR-lite UE may stop the cell search for the corresponding carrier frequency by determining or assuming that no cells for the corresponding carrier frequency support NR-lite UEs. The NR-lite UE may attempt to camp on by searching for another cell of another carrier frequency.

Alternatively, in some embodiments, if a separate initial UL BWP for the NR-lite UE is not defined, if the bandwidth of the initial UL BWP is greater than cells supportable by the NR-lite UE, the UE considers the corresponding cell to be barred and attempts camping by searching for another cell within the same frequency. Alternatively, by assuming that all cells of the corresponding frequency do not support NR-lite UEs, it may stop the search for each cell of the corresponding frequency and attempt camping by searching for another cell of another frequency.

In some embodiments, if a separate initial DL/UL BWP is used, the gNB may notify each of initialdown linkbwp2, initialluplinks BWP2, PDCCH-ConfigCommon2(coreset and searchspace), etc., and even notify BCCH configuration information for SIB transmission and PCCH configuration information for paging transmission separately for NR-lite UEs. At this time, initialdown bwp2 may be formed as a subset of the initialdown bwp, and NR-lite UE and general UE may have different locationiandbandwidth information and jointly use the remaining parameters (subcarrierspace, pdcch-ConfigCommon, etc.). That is, only locationAndBandwidth information is signaled in the initialDownlinkBWP2, and the remaining parameters utilize information of the existing initialdwlpp for the general UE, thereby reducing signaling overhead. The same applies to initialUplinkBWP. That is, only locationAndBandwidth information is different, and the NR-lite UE and the normal UE can share other information of initialuplinklonbwp.

Although not shown in fig. 9, if it is determined whether access is possible and it is determined that the cell is not barred through the MIB and the SIB1, the NR-lite UE may receive other SIB information from the corresponding cell, and the other SIB information may include information individually indicating which cells within frequency (same frequency) or between frequency (different frequencies) support the NR-lite UE or the NR-lite UE. The NR-lite UE can more efficiently access the network through other SIB information if a cell is reselected or handed over due to a signal strength change, a collapse of a corresponding cell, a channel state change. For example, other SIB information may be used to reselect NR-lite enabled cells. Alternatively, the NR-lite UE may start receiving a paging message from a corresponding cell and recognize whether there is downlink data from the network.

Meanwhile, the NR-lite UE may perform an RRC connection procedure to establish an RRC connection. The NR-lite UE may perform a random access procedure.

In step 907, the NR-lite UE may transmit a random access preamble based on initial BWP information of the NR-lite UE. If the NR-lite UE and the normal NR UE perform random access using the same initial DL BWP and initial UL BWP and the same random access parameters, the UE may operate as follows.

In step 909, the NR-lite UE may receive the random access response. The gNB may transmit a random access response in response to the random access preamble of the NR-lite UE.

In step 911, the NR-lite UE may transmit MSG3 for the NR-lite UE. An NR-lite UE may acquire uplink resources for MSG3 transmission by receiving RARs from the gbb. Next, the NR-lite UE, which is limited in terms of data rate of transmission and reception, needs to be notified in this random access step before transmitting UE capability information to prevent the gNB from randomly transmitting data, and thus the UE can transmit MSG3 by selecting the following LCID according to the type of message to be transmitted in MSG 3.

LCID A. used by NR-lite UEs (i.e., UEs that are limited in terms of BW and maximum TB size), a 48-bit CCCH SDU message is sent.

LCID B for transmitting 48 bits of CCCH SDU information.

LCID C for transmitting 64-bit CCCH SDU messages.

(A, B and C are designated integer values defined by the standard, labeled A, B and C for convenience.)

Thus, if the CCCH SDU to be transmitted in MSG3 is an RRCSetupRequest, the UE selects and reports one of LCID a and LCID B, and if the UE is an NR-lite UE, LCID a is selected.

Further, if the CCCH SDU to be transmitted in MSG3 is RRCResumeRequest, one of LCID B and LCID C is selected and reported. The RRCResumeRequest message is a message for transitioning from the RRC _ INACTIVE state to the RRC _ CONNECTED state, does not need to be re-notified to the NR-lite UE, and is determined according to the size of the RRCResumeRequest message because the gNB has entered the RRC _ CONNECTED state and notified the NR-lite UE.

Further, if the CCCH SDU to be transmitted in MSG3 is rrcreestablstrimentrequest, the UE selects and reports LCID B. This is for the RRC _ CONNECTED state UE to recover from the radio channel condition degradation, and because there is no need to re-notify the NR-lite UE, because the NR-lite UE is already known by the gNB and the rrcreestablshmentrequest has a single size of 48 bits.

Alternatively, the NR-lite UE may consider a scenario where LCID a is always used for CCCH transmission.

In step 913, the NR-lite UE may receive the RRC response message. In response to MSG3 transmissions, the NR-lite UE may receive MSG 4 for identifying whether the corresponding MSG3 has been correctly transmitted. For example, the NR-lite UE may receive a response message (i.e., RRCSetup/rrcresum/rrcreestablstrism) of the RRC message transmitted in MSG 3.

Embodiments have been described in which the LCID included in MSG3 informs the UE that it is an NR-lite UE, but UEs performing random access attempts through MSG3 may otherwise indicate the NR-lite UE to the gNB. For example, the NR-lite UE may explicitly inform that MSG3 is MSG3 of the NR-lite UE by using spare bits of an RRC message included in MSG 3. Also, for example, the NR-lite UE may explicitly inform that the UE attempting random access is an NR-lite UE by using a separate value in establistensincause in the RRCSetupRequest message.

Meanwhile, according to the embodiment, if different initial UL BWPs (initial downlink BWPs 2) are set for NR-lite UEs or if the same initial DL BWP and initial UL BWP are used but the random access related parameters are set differently, the UEs may not need to separately inform that the corresponding UEs are NR-lite UEs through MSG 3. For example, each uplink transmission sent by the UE may be an initial UL BWP separate from the transmissions of the normal UE. Alternatively, the random access resource may be a PRACH resource separate from the transmission of the normal UE, for example. In this case, the gNB only receives MSG1 of NR-lite UEs, and can obtain that the UE transmitting MSG1 is an NR-lite UE.

Instead, the gNB may set up a separate search space for the NR-lite UE to receive MSG2 using the initial DL BWP 2. Alternatively, the preamble transmission of MSG1 may be distinguished and set in initialdown linkbwp 2. In this case, since the identifiers of the random access preambles transmitted in MSG2 reception are different, the NR-lite UE can receive MSG2 without confusion with normal UEs. Alternatively, the gNB can distinguish between MSG 2's of two UEs separately by adding the offset of the NR-lite UE to the RA-RNTI used to scramble the PDCCH in the MSG2 transmission. Alternatively, the gNB may include an indicator in information included in the PDCCH used in MSG2 transmissions that explicitly indicates that the scheduling is for NR-lite UEs.

Although not shown in fig. 9, if the NR-lite UE never accesses the network and the core network (MME of LTE or AMF of NR) has no UE capability information, the core network may command the gNB to receive the UE capability information. The gNB may request a UE capability information transmission from the NR-lite UE. The NR-lite UE may send UE capability information to the gNB if the request is received. At this time, the NR-lite UE may indicate that the UE transmitting the UE capability information to the gNB is the NR-lite UE by including a specific field (or a specific value) in the capability information. For example, as described above, the NR-lite UE may inform the capability with 1-bit information including the characteristics of NR-lite (limited SCS/BW/TB size). Therefore, in order to handover a corresponding UE to another gNB, the gNB can perform handover only when the target gNB supports the NR-lite UE by using corresponding 1-bit information.

Fig. 9 has described that the random access procedure is performed in the initial access step, but the description of steps 907 to 913 may be performed in other procedures than the initial access. For example, if a paging message is received from a cell and downlink data is to be received, or if uplink data to be transmitted occurs, the NR-lite UE needs to transition to the RRC _ CONNECTED mode for corresponding data transmission and reception, and random access may be performed for this.

Fig. 10 shows a functional configuration of a base station in a wireless communication system according to various embodiments of the present disclosure. Terms such as "… unit" or "processor" used hereinafter refer to a unit for processing at least one function or operation and may be implemented using hardware, software, or a combination of hardware and software.

Referring to fig. 10, the base station includes a wireless communication unit 1001, a backhaul communication unit 1003, a storage unit 1005, and a control unit 1007.

The wireless communication unit 1001 performs a function of transmitting and receiving a signal through a radio channel. For example, the wireless communication unit 1001 performs a function of converting between a baseband signal and a bit string according to a physical layer standard of the system. For example, in data transmission, the wireless communication unit 1001 generates a complex symbol by encoding and modulating a transmission bit string. In addition, in data reception, wireless communication section 1001 recovers the received bit string by demodulating and decoding the baseband signal. Further, the wireless communication unit 1001 up-converts a baseband signal into a Radio Frequency (RF) band signal, then transmits it via an antenna, and down-converts an RF band signal received via the antenna into a baseband signal.

To this end, the wireless communication unit 1001 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Further, the wireless communication unit 1001 may include a plurality of transmission/reception paths. Furthermore, the wireless communication unit 1001 may comprise at least one antenna array comprising a plurality of antenna elements. In terms of hardware, the wireless communication unit 1001 may include a digital unit and an analog unit, and the analog unit may include a plurality of sub-units according to an operating power and an operating frequency. According to various embodiments, the wireless communication unit 1001 may comprise a unit for forming beams, i.e. a beam forming unit. For example, the wireless communication unit 1001 may include a massive Multiple Input Multiple Output (MIMO) unit (MMU) for beamforming.

The wireless communication unit 1001 can transmit or receive a signal. To this end, the wireless communication unit 1001 may include at least one transceiver. For example, the wireless communication unit 1001 may transmit a synchronization signal, a reference signal, system information, a message, control information, data, and the like. Further, the wireless communication unit 1001 may perform beamforming. In order to impart directivity to a signal to be transmitted or received based on the configuration of the control unit 1007, the wireless communication unit 1001 may apply beamforming weights to the signal. According to the embodiment, the wireless communication unit 1001 may generate a baseband signal according to a scheduling result and a transmission power calculation result. Further, the RF unit in the wireless communication unit 1001 may transmit the generated signal via an antenna.

The wireless communication unit 1001 transmits and receives signals as described above. Accordingly, all or part of the wireless communication unit 1001 may be referred to as a "transmitter", "receiver", or "transceiver". Further, hereinafter, transmission and reception on a radio channel are used as meaning of the above-described processing involving the wireless communication unit 1001.

The backhaul communication unit 1003 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 1003 converts a bit string transmitted from the base station to another node (e.g., another access node, another base station, an upper node, or a core network) into a physical signal, and converts a physical signal received from the other node into a bit string.

The storage unit 1005 stores basic programs for operating the base station, application programs, and data such as setting information. The storage unit 1005 may include a memory. The storage unit 1005 may include a volatile memory, a non-volatile memory, or a combination of volatile and non-volatile memories. The storage unit 1005 provides the stored data at the request of the control unit 1007. According to an embodiment, the storage unit 1005 may include a UE information management unit including UE information. The UE information may include capability information of each UE (e.g., whether it is an NR-lite UE). If the UE re-accessed through the storage unit is an NR-lite UE, the gNB can signal or allocate resources based on the constraints of the NR-lite UE.

The control unit 1007 controls general operations of the base station. For example, the control unit 1007 transmits and receives signals through the wireless communication unit 1001 or the backhaul communication unit 1003. Further, the control unit 1007 records data in the storage unit 1005 and reads data from the storage unit 1005. The control unit 1007 may perform a function of a protocol stack requested by a communication standard. To this end, the control unit 1007 may include at least one processor. According to various embodiments, the control unit 1007 may control the base station to perform operations according to the various embodiments described above. According to an embodiment, the gNB may determine that the UE performing the access procedure is an NR-lite UE. Further, according to embodiments, the gNB may schedule NR-lite UEs according to conditions (e.g., SCS, TB size, BW size) required for the NR-lite UEs.

The configuration of the base station 110 shown in fig. 10 is merely an example of a base station, and examples of a base station implementing various embodiments of the present disclosure are not limited to the configuration shown in fig. 10. That is, some configurations may be added, deleted, or changed according to various embodiments.

Fig. 10 describes the base station as one entity, but the present disclosure is not limited thereto. Base stations according to various embodiments of the present disclosure may be implemented to build access networks with distributed deployments as well as integrated deployments. According to an embodiment, a base station may be divided into a Central Unit (CU) and a Digital Unit (DU) and may be implemented such that the CU performs an upper layer (e.g., PDCP, RRC) and the DU performs a lower layer (e.g., MAC, PHY). The DU of the base station can establish beam coverage on the radio channel.

Fig. 11 shows a functional configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure. Terms such as "… unit" or "processor" used hereinafter mean a unit for processing at least one function or operation, and may be implemented using hardware, software, or a combination of hardware and software. A terminal according to various embodiments may be an NR-lite UE. According to embodiments, the information that a normal UE recognizes an NR-lite UE and ignores or discards the information may also be understood as an embodiment of the present disclosure.

Referring to fig. 11, the terminal includes a communication unit 1101, a storage unit 1103, and a control unit 1105.

The communication unit 1101 may perform a function of transmitting and receiving signals through a radio channel. For example, the communication unit 1101 performs a conversion function between a baseband signal and a bit string according to the physical layer standard of the system. For example, in data transmission, the communication unit 1101 generates complex symbols by encoding and modulating a transmission bit string. Further, in data reception, the communication unit 1101 restores a received bit string by demodulating and decoding a baseband signal. Further, communication section 1101 up-converts a baseband signal into an RF band signal, transmits the signal via an antenna, and down-converts an RF band signal received via the antenna into a baseband signal. For example, the communication unit 1101 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

Further, the communication unit 1101 may include a plurality of transmission and reception paths. Further, the communication unit 1101 may include an antenna unit. The communication unit 1101 may comprise at least one antenna array comprising a plurality of antenna elements. In terms of hardware, the communication unit 1101 may include digital circuitry and analog circuitry (e.g., RF integrated circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented as a single package. Further, the communication unit 1101 may include a plurality of RF chains. The communication unit 1101 may perform beamforming. In order to give directivity to a signal to be transmitted or received according to the configuration of the control unit 1105, the communication unit 1101 may apply beamforming weights to the signal. According to an embodiment, the communication unit 1101 may include an RF block (or RF unit). The RF block may include a first RF circuit associated with the antenna and a second RF circuit associated with baseband processing. The first RF circuit may be referred to as an RF antenna (a). The second RF circuit may be referred to as an RF baseband (B).

Further, the communication unit 1101 may transmit and receive signals. To this end, the communication unit 1101 may include at least one transceiver. The communication unit 1101 may receive a downlink signal. The downlink signal may include a Synchronization Signal (SS), a Reference Signal (RS) (e.g., a cell-specific reference signal (CRS), a Demodulation (DM) -RS), system information (e.g., MIB, SIB, remaining system information (RMSI), Other System Information (OSI)), a configuration message, control information, or downlink data. In addition, the communication unit 1101 may transmit an uplink signal. The uplink signal may include a random access related signal (e.g., Random Access Preamble (RAP) (or Msg1, Msg3)), a reference signal (e.g., Sounding Reference Signal (SRS), DM-RS), or BSR.

Specifically, the communication unit 1101 may include an RF processing unit and a baseband processing unit. The RF processing unit performs functions of transmitting and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processing unit up-converts a baseband signal provided from the baseband processing unit into an RF band signal, then transmits it via the antenna, and down-converts an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. In fig. 2H, only one antenna is shown, but the terminal may include a plurality of antennas. Further, the RF processing unit may include a plurality of RF chains. Further, the RF processing unit may perform beamforming. For beamforming, the RF processing unit may adjust the phase and amplitude of each signal transmitted and received via multiple antennas or antenna elements.

The baseband processing unit performs a conversion function between the baseband signal and the bit string according to a physical layer standard of the system. For example, in data transmission, a baseband processing unit generates complex symbols by encoding and modulating a transmission bit string. Further, in data reception, the baseband processing unit restores a received bit string by demodulating and decoding a baseband signal provided from the RF processing unit. For example, according to the OFDM scheme, in data transmission, a baseband processing unit generates complex symbols by encoding and modulating a transmission bit string, maps the complex symbols to subcarriers, and then generates OFDM symbols through an Inverse Fast Fourier Transform (IFFT) operation and CP (cyclic prefix) insertion. Also, in data reception, the baseband processing unit segments the baseband signal provided from the RF processing unit based on the OFDM symbol, restores the signal mapped to the subcarrier through a Fast Fourier Transform (FFT) operation, and then restores the received bit string through demodulation and decoding.

The communication unit 1101 transmits and receives signals as described above. Accordingly, all or part of the communication unit 1101 may be referred to as a transmitter, receiver or transceiver. Further, the communication unit 1101 may comprise a plurality of communication modules to support a plurality of different radio access technologies. Further, the communication unit 1101 may include different communication modules to process signals of different frequency bands. For example, the different radio access technologies may include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), and so on. Further, the different frequency bands may include an ultra high frequency (SHF) (e.g., 2.5GHz, 5GHz) frequency band and a millimeter wave (e.g., 60GHz) frequency band. Further, the communication unit 1101 may use the same type of radio access technology on different frequency bands (e.g., unlicensed band for Licensed Assisted Access (LAA), Citizen Broadband Radio Service (CBRS) (e.g., 3.5 GHz)).

The storage unit 1103 stores a basic program for operating the terminal, an application program, and data such as setting information. The storage unit 1103 may include volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 1103 stores basic programs, application programs, and data such as setting information for the operation of the terminal. Specifically, the storage unit 1103 may store information related to a wireless LAN node that performs wireless communication using a wireless LAN access technology. The storage unit 1103 provides the stored data at the request of the control unit 1105. According to an embodiment, the storage unit 1103 may store bandwidth information (e.g., initialldownlinkbwp 2, initialluplinkbwp 2) of the NR-lite UE.

The control unit 1105 controls the general operation of the terminal. For example, the control unit 1105 transmits and receives signals through the communication unit 301. Further, the control unit 1105 records data in the storage unit 1103 and reads data from the storage unit 1103. The control unit 1105 may perform the functions of a protocol stack required by the communication standard. To this end, the control unit 1105 may include at least one processor. The control unit 1105 may comprise at least one processor or microprocessor or may be part of a processor. In addition, a part of the communication unit 1001 and the control unit 1105 may be referred to as a Communication Processor (CP). The control unit 1105 may include various modules for communication. According to various embodiments, the control unit 1105 may control the terminal to perform operations according to various embodiments to be described.

The control unit 1105 controls the general operation of the terminal. For example, the control unit 1105 transmits and receives signals through the communication unit 1101. Further, the control unit 1105 records data in the storage unit 1103 and reads data from the storage unit 1103. To this end, the control unit 1105 may include at least one processor. For example, the control unit 1105 may include a CP for controlling communication and an Application Processor (AP) for controlling an upper layer such as an application program. According to an embodiment of the present invention, the control unit 1105 may include a multi-connection processor for processing to operate in a multi-connection mode. For example, the control unit 1105 may control the terminal to perform operations according to the various embodiments described above. According to various embodiments, the control unit 1105 determines whether access to a corresponding cell (i.e., a cell providing at least one of the received MIB and SIB1) is possible through at least one value of the received MIB and SIB1, and if it is determined to be possible, indicates to perform a random access procedure (e.g., the random access procedure of fig. 4 or fig. 7).

The method according to the embodiments described in the claims or the specification of the present invention can be implemented in software, hardware, or a combination of hardware and software.

As for software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors of the electronic device. The one or more programs may include instructions for controlling an electronic device to perform a method according to an embodiment of the invention described in the claims or specification.

Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, Read Only Memory (ROM), electrically erasable programmable ROM (eeprom), magnetic disk storage devices, Compact Disk (CD) -ROM, Digital Versatile Disks (DVD) or other optical storage devices, and magnetic cassettes. Alternatively, it may be stored in a memory combining some or all of these recording media. Multiple memories may be included.

Further, the program may be stored in an attachable storage device accessible via a communication network such as the internet, an intranet, a LAN, a wide area LAN (wlan), or a Storage Area Network (SAN), or by a combination of these networks. Such a storage device may be accessible through an external port to a device implementing an embodiment of the present invention. Furthermore, a separate storage device on the communication network may access the device performing an embodiment of the invention.

In particular embodiments of the invention, elements included in the invention may be referred to in the singular or plural. However, for convenience of explanation, the singular or plural expressions are appropriately selected according to the proposed circumstances, the present invention is not limited to a single element or a plurality of elements, an element expressed in the plural expression may be configured as a single element, and an element expressed in the singular expression may be configured as a plurality of elements.

Meanwhile, although specific embodiments have been described in the explanation of the present invention, it should be noted that various changes may be made therein without departing from the scope of the present invention. Accordingly, the scope of the present invention is not limited or restricted by the described embodiments, and is defined not only by the scope of the appended claims, but also by their equivalents.

Claims

1. A method of operation of a terminal in a wireless communication system, comprising:

receiving system information from a cell of a base station;

determining whether the cell supports a New Radio (NR) lite based on the system information; and

if the cell supports NR lite, performing a random access procedure for the cell,

wherein for a terminal performing NR lite, at least one of a subcarrier spacing (SCS), a Transport Block (TB) size, or a bandwidth part (BWP) is reduced to a specified value compared to other terminals not performing NR lite.

2. The method of claim 1, wherein determining whether the cell supports NR lite comprises:

determining whether the cell supports NR lite based on information indicating SCS of a Master Information Block (MIB) as system information, control region information of a System Information Block (SIB)1, and information related to intra-frequency reselection.

3. The method of claim 1, wherein determining whether the cell supports NR lite comprises:

determining whether the cell supports NRlite according to a 1-bit indicator of the MIB as system information.

4. The method of claim 1, wherein determining whether the cell supports NR lite comprises:

obtaining initial BWP information from the system information; and

determining whether the cell supports NR lite by comparing the initial BWP information and a bandwidth value of NR lite.

5. The method of claim 1, wherein determining whether the cell supports NR lite comprises:

determining whether initial BWP information of NR lite is set according to the system information; and

determining that the cell supports NR lite if initial BWP information of NR lite is set.

6. The method of claim 1, wherein performing a random access procedure comprises:

a random access preamble is transmitted and,

wherein the random access preamble is for indicating support of NR lite.

7. The method of claim 1, wherein performing a random access procedure comprises:

receiving a Random Access Response (RAR) from the base station,

wherein the RAR comprises information indicating that the cell supports NR lite.

8. The method of claim 1, wherein performing a random access procedure comprises:

in response to the RAR, an uplink message is sent,

wherein a logical channel identifier of the uplink message is used to indicate support of NR lite.

9. The method of claim 1, further comprising:

and transmitting capability information indicating whether the terminal supports NR lite to the base station.

10. A method of operation of a base station in a wireless communication system, comprising:

transmitting system information indicating whether a cell supports a New Radio (NR) lite; and

a random access procedure with the terminal is performed,

11. The method of claim 10, wherein the system information indicates the cell's support for NR lite by a combination of: information indicating SCS of a Master Information Block (MIB), control region information of a System Information Block (SIB)1, and information related to intra-frequency reselection; or

A 1-bit indicator of the MIB; or

Initial BWP information configuration of NR lite.

12. The method of claim 10, wherein performing a random access procedure comprises:

sending a random access preamble;

receiving a Random Access Response (RAR) from a base station; and

in response to the RAR, an uplink message is sent,

wherein a logical channel identifier of the random access preamble or the uplink message is used to indicate that the NR lite is supported, an

The RAR includes information indicating that a cell supports NR lite.

13. The method of claim 10, further comprising:

capability information indicating whether the terminal supports NR lite is received from the terminal.

14. A terminal in a wireless communication system, comprising:

at least one transceiver; and

at least one processor coupled to the at least one transceiver,

wherein the at least one processor is configured to perform one of the methods of claim 1 through claim 9.

15. A base station in a wireless communication system, comprising:

at least one transceiver; and

at least one processor coupled to the at least one transceiver,

wherein the at least one processor is configured to perform one of the methods of claim 10 through claim 13.